/* Universidad del Valle de Guatemala
 * Stack.java
 * Mariana Castillo, 12374
 * Julio Maldonado, 12377
 * Seccion 30, Algoritmos y Estructura de Datos
 * Fecha: 03/07/13
 * Interfaz que contiene la firma de los metodos implementados por el arraylist, vector y las listas*
 */
package hojat4;


public interface Stack<E> {
    public void push(E item);
   // pre: 
   // post: item is added to stack
   // will be popped next if no intervening push
   
   public E pop();
   // pre: stack is not empty
   // post: most recently pushed item is removed and returned
   public E peek();
   // pre: stack is not empty
   // post: top value (next to be popped) is returned
   
   public boolean isEmpty();  
   // post: returns true if and only if the stack is empty
  
   public int size();
   // post: returns the number of elements in the stack
   
}
    


   